Appendix 3, continued. Species life history notes 



• Sevenspine bay shrimp: Crangon septemspinosa 

 is also known as the sand shrimp. It is the most 

 common shallow water shrimp in the Gulf of Maine and 

 is found primarily in eelgrass beds and sandy bottoms. 

 This species exhibits seasonal movements from shal- 

 low to deeper water and is relatively inactive in the 

 winter months. Soon after mating females fertilize and 

 extrude eggs onto their pleopods, where they are held 

 for approximately one month until hatching as larvae 

 (Haefner 1979). There is some evidence showing two 

 separate spawning periods in the northern part of its 

 range (Corey 1987). For the purposes of the ELMR 

 program, the spawning stage (S) is defined as the 

 period of mating/fertilization/egg extrusion; the larval 

 stage (L) consists of the protozoeal and zoeal stages; 

 and the egg stage (E) is synonymous with ovigerous 

 females. 



• American lobster: Homarus americanus is found 

 primarily in salinities >20 ppt (Cooper and Uzmann 

 1 980, MacKenzie and Moring 1 985). Eggs and larvae 

 are less tolerant of low salinity than juveniles and 

 adults. Mating typically occurs every other year for 

 individual females, when the male places a spermato- 

 phore into a freshly molted female (but intermolt matings 

 have been reported). Eggs are normally extruded 11- 

 13 months later (MacKenzie and Moring 1985) and 

 multiple fertilizations are possible from a single sper- 

 matophore. Eggs are carried 9-1 1 months and hatch in 

 spring to early fall depending upon temperature. Ber- 

 ried females are present throughout the year but num- 

 bers may be lower in the summer as eggs are hatched 

 and molting/mating is occurring. Pelagic larvae molt 

 four times, then settle to bottom as early benthic phase 

 lobsters with adult characteristics. For the purposes of 

 the ELMR program, the spawning stage (S) is defined 

 as the period of fertilization/egg extrusion; the larval 

 stage (L) consists of the mysis and postlarval stages; 

 and the egg stage (E) is synonymous with ovigerous 

 (berried) females. 



• Green crab: Carcinus maenas is the most common 

 shore crab found intertidally and subtidally in the Gulf 

 of Maine down to at least 6 ppt. Abundance in mid- 

 coast and northern Maine may be affected by 

 interannual variations in temperature as this species 

 nears the edge of its range. Mating typically occurs in 

 the summer and/or fall and hatching of eggs occurs in 

 the spring and/or summer (Berrill 1982, Williams 1984). 

 For the purposes of the ELMR program, the spawning 

 stage (S) is replaced by mating (M), which designates 

 copulation only; the larval stage (L) consists of the 

 zoeal and megalopal stages; and the egg stage (E) is 

 synonymous with ovigerous (sponge) females. 



• Green sea urchin: Strongylocentrotus 

 droehbachiensis is usually not found in salinities < 29 

 ppt, however, it does occur intertidally as well as 

 subtidally in the Gulf of Maine. Spawning seems to 

 coincide with the spring phytoplankton bloom (Starr et 

 al. 1990), but there is some anecdotal evidence 

 suggesting more than one spawning event. Sperm and 

 eggs are shed into the water where fertilization takes 

 place. Within approximately 12 hours of fertilization, 

 the blastula becomes ciliated and free swimming. 

 Gastrulation ensues and a planktonic "echinopluteus" 

 larvae develops and persists for up to 3-4 months. Late 

 in the larval stage, usually early summer, the test 

 begins to form and the echinopluteus sinks to the 

 bottom as a settling juvenile that is < 1 mm in diameter. 

 This settlement usually occurs over a 4-6 week period 

 showing a peak of young-of-year juveniles (L. Harris, 

 pers. comm.). Growth rates are highly variable and it 

 takes approximately 1 .5-3.5 years for individuals to 

 reach maturity at >20 mm diameter. There may be 

 some local migration to deeper water to overwinter but 

 this species is primarily a slow moving, shallow water 

 species in the Gulf of Maine (Himmelman et al. 1 983). 

 Harvesting of ripe animals for high quality roe has 

 developed fairly recently and it is unclear how this 

 fishery is impacting local populations (Chenoweth 1 992). 



• Jonah and Atlantic rock crabs: Cancer borealis 

 and C. irroratus are found primarily in salinities >20 ppt 

 and are sometimes grouped together (Krouse 1980, 

 Williams 1984). Cancer irroratus prefers sandy sub- 

 strates and is usually in shallower water, whereas 

 Cancer borealis prefers rockier substrates, is usually 

 in deeper water, and is less tolerant of low salinities. 

 Juvenile C. borealis are seldom recorded from inshore 

 areas and are easily confused with juvenile C. irroratus 

 (Williams and Wahle 1992). For the purposes of the 

 ELMR program, the spawning stage (S) is defined as 

 mating/fertilization/egg extrusion; the larval stage (L) 

 consists of the zoeal and megalopal stages; and the 

 egg stage (E) is synonymous with ovigerous (sponge) 

 females. 



Fishes. The use of salinity zones generally describes 

 the spatial distribution of estuarine fishes. However, for 

 some species a combination of habitat characteristics, 

 such as bottom type, water temperature, bathymetry, 

 etc., would more accurately indicate these distribu- 

 tions. Specific habitat requirements and life history 

 characteristics of a number of fishes are presented 

 below. 



• Spiny dogfish: Squalus acanthias is a summer 

 migrant to the Gulf of Maine, moving offshore in the 

 winter and inshore in the summer. Catch statistics 

 show high inter- and intra-annual variability due to their 

 tendency to school by size and sex. Males and mature 

 females are most common inshore. Spiny dogfish are 

 long lived and ovoviviparous. Fecundity is low (2-15 



154 



